The type of reclining chair to which this invention generally pertains is a three position chair capable of going from a substantially upright and closed position to a first reclining or "TV" position, and then to a fully reclined position. These positions are generally defined by movement of the backrest and an extensible footrest relative to the chair base frame; in some instances, the seat frame is also made movable relative to the chair base. Movement of the reclining chair between its various positions is typically accomplished through force exerted against either the backrest or the arms of the chair by the occupant, thereby causing the backrest to tip backwardly and the footrest to be extended.
It has been very common to use a scissors type or "lazy tong" linkage for the footrest extension mechanism in order to extend the footrest sufficiently forward of the chair. This scissors type linkage has notable disadvantages, foremost among which is the safety problem presented by the scissoring action of the linkage itself, which is capable of causing serious injury, such as to a finger or other extremity caught in the mechanism when it is retracted quickly from its extended position. Additionally, the multiplicity of pivot joints in the scissors linkage are all subject to wear and fatigue, often resulting in a loosening of the mechanism with the consequent failure of the footrest to assume a tightly retracted condition with the chair. Such scissor linkages also have relatively little lateral strength and are subject to easy damage from sideways forces applied to the footrest when extended.
As an alternative to the scissor type footrest extension mechanisms, extension mechanisms have been devised which use longitudinally extending rails which serve to carry the footrest outwardly and upwardly. For example, U.S. Pat. No. 2,936,819 uses rails carrying a footrest support. The rails are slidably mounted in longitudinally slotted brackets attached to the seat and are moved forwardly with respect to the seat as a consequence of relative movement between the seat and a supporting base. U.S. Pat. No. 3,869,169 shows a footrest support which is carried by a pair of parallel rails movable endwise on the chair, which rails are extended and retracted by a handle-driven drive linkage. A linkage is also provided to change the angularity of the footrest relative to the rails.
With specific regard to the mechanism disclosed in the above-identified U.S. Pat. No. 3,869,169, the system provides for movement of the rails through the use of rollers on which the rails or "glide bars" roll. In actual use, this causes the top edge of the footrest to "hang" on the front of the cushion of the seat when trying to open the chair. Due to the fact that the footrest advances relatively straight out on these rollers, the footrest mechanism also has an unnatural movement to the TV position. More specifically, the occupant of the chair is first hit behind the knees by the advancing footrest, with the footrest thereupon sliding down the length of the occupants leg. The same undesirable mction likewise occurs in reverse when retracting the footrest. This relative endwise movement of the glide bars further renders retraction of the footrest difficult due to the fact that the natural motion for a person in a chair is to push downward on the footrest to close it; more horizontal leg motion is therefore required of the occupant because of the relatively straight line operation of the '169 mechanism. This can result in use of excessive downward pressure placed on the footrest mechanism, which will bend it. Also, use of rollers in the footrest extension mechanism creates a need for relatively close tolerance levels in production and manufacture of the mechanism, with a consequent increase in loose and unacceptable chairs reaching retail stores.